HR: 15:45h
AN: SH54A-02    [Abstracts]
TI: Energetic Particle Effects Associated With Reconnection in the Solar Wind
AU: * Gosling, J T
EM: jgosling@lanl.gov
AF: Los Alamos National Laboratory, MS D466, Los Alamos, NM 87545 United States
AU: Skoug, R M
EM: rskoug@lanl.gov
AF: Los Alamos National Laboratory, MS D466, Los Alamos, NM 87545 United States
AU: Haggerty, D K
EM: Dennis.Haggerty@jhuapl.edu
AF: Johns Hopkins University, Applied Physics Lab MP3-E184 11100 Johns Hopkins Rd, Laurel, MD 20723-6099 United States
AB: Reconnection is often invoked, for example in the contexts of the solar atmosphere and the geomagnetic tail, as a means of accelerating a small number of particles to energies well above 40 keV. The acceleration presumably results either from particle displacement relative to the electric field that must be present along the so-called reconnection line where reconnection occurs or from particle encounters with slow mode shocks within reconnection exhausts. We have recently obtained direct evidence for local, quasi-stationary, magnetic reconnection in the solar wind using plasma and magnetic field measurements obtained by the Advanced Composition Explorer, ACE. The prime evidence consists of intervals of accelerated or decelerated plasma flow observed within magnetic field reversal regions that we interpret as encounters with (generic) Petschek-type reconnection exhausts that are bounded by Alfven waves. We have made a preliminary examination of energetic particle observations obtained by ACE for the first 6 reconnection exhausts identified. We find evidence only for relatively minor modulations in the flux of greater than 40 keV electrons in association with these events (mostly small decreases in particle intensity that we suspect are associated with topological changes in the magnetic field), and no evidence for any substantial electron acceleration within the exhausts or the surrounding separatrix layers. This result contrasts strongly with interpretations given to energetic electron observations in the geomagnetic tail presumably associated with reconnection. On the other hand, we find some evidence for proton acceleration to energies greater than 50 keV in the heart of one of the exhausts and relatively small modulations in energetic proton intensity in two others (probably associated with changes in magnetic topology). We believe these results have implications for particle acceleration models invoking reconnection in other contexts.
DE: 2114 Energetic particles, heliospheric (7514)
DE: 2134 Interplanetary magnetic fields
DE: 2164 Solar wind plasma
DE: 7514 Energetic particles (2114)
DE: 7835 Magnetic reconnection
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2005 Joint Assembly